This invention relates to fastening members, and more particularly to a wall fastener, such as a toggle bolt, which can attach articles to an apertured wall, and the like, and can be removed for subsequent use.
Wall fasteners, such as toggle bolts, are utilized in connection with an apertured wall where it is desired to attach an article to the wall. Typically, such toggle bolts are utilized with hollow walls so that the space behind the wall can accommodate the toggle mechanism and provide the space for the toggle to pivot in a direction transverse to the axis of the bolt in order to abut the rear surface of the wall.
The standard toggle bolt includes a bolt which passes through an engaging nut which in turn is held at the vertex of V-shaped wings. The wings are spring biased into an open direction. When inserting the toggle bolt, the wings are held closed in order to insert the toggle bolt through the aperture. Once the toggle bolt has been inserted through the wall, the wings are spread apart by the force of the biasing springs. As the bolt is threaded into the receiving nut, the wings are drawn toward the rear surface of the wall and are tightly held in place. The bolt can pass through a hook, or the like, and will securely retain an object attached to the wall.
One problem with such commonly used toggle bolts is that they cannot be reused. In order to withdraw the toggle bolt from the wall, the bolt must be unthreaded, causing the wings to fall into the open space behind the apertured wall. As a result, the wings cannot be extracted through the aperture and the toggle bolt cannot be reused a second time.
Numerous reusable toggle bolts have been suggested in the prior art, however, none of these have been widely accepted because of the limitations therein. For example, U.S. Pat. No. 2,024,871 described a toggle bolt and sleeve arrangement whereby the wings can be threaded into a portion of the sleeve which forces the wings to collapse, and subsequently both the bolt and sleeve can be removed. However, this mechanism requires a special type sleeve whose size must be fitted to the thickness of the wall and accordingly has limited use since numerous sizes therefore must be provided. Furthermore, the requirements of the sleeve increases the cost of the device and the difficulty for its use.
U.S. Pat. No. 2,203,146 describes another type of reusable fastening device which utilizes a spring held toggle housing which is caused to pivot from an inserted position into a locked position by means of a special tool inserted through the spring. Since a special tool is required to insert and remove the toggle device, an individual must retain the tool after the fastening device has been inserted, otherwise he will not be able to later remove the fastening device. Furthermore, the tightness with which the fastening device is held onto the wall depends on the spring force. As a result, with continued use, the spring will stretch and will not hold as tightly. Also, a heavier weighted object will cause the spring to expand further and will thereby not be held as securely to the wall.
A further reusable toggle bolt is described in U.S. Pat. No. 2,224,023, which utilizes a resilient member which flexes in various directions in order to accommodate bending of the wings in a first direction for insertion and in an opposing direction for removal. However, the flexing mechanism thereby is continuously subject to stress failure, must be specially manufactured, and prevents the toggle bolt from being sufficiently tightened in place to hold very heavy articles.
Still a further toggle bolt is described in U.S. Pat. No. 3,127,808, which utilizes the bolt only for insertion and removal of the toggle fastener. A separate threaded holder is required which fits into a sleeve which must be inserted into the wall. The sleeve extends into a toggle housing which pivots due to the force of gravity. As a result, numerous parts are required which makes the device complex. The sleeve must be fitted to the wall thickness and is therefore pre-sized which limits universal use of the fastening device for all types of walls. Furthermore, the inserting and removing bolt must be kept and cannot be lost, otherwise the device will not be able to be removed. Furthermore, it requires gravity to pivot the toggle housing into its locked position, and can therefore only be utilized in conjunction with vertical walls.
Yet another reusable toggle bolt is described in U.S. Pat. No. 4,079,655 which threads a biasing support member onto the bolt and retains the wings unthreaded from the bolt. As the bolt is unthreaded from the wall, the biasing support members are pulled into the aperture which in turn brings the wings together thereby collapsing them so that they can be removed from the wall. However, the biasing support members are continuously deformed and squeezed through the openings and thereby can snap and break apart. Furthermore, it does not provide for a secure connection between the toggle mechanism and the bolt and thereby provides for a device which can be easily broken.
It is therefore evident that although numerous devices have been suggested in the prior art, there is still a need for a suitable removable toggle bolt.